The invention relates to heating and ventilating units for motor cars of the type in which air temperature regulation is effected by movement of a heat exchanger's operative surface into an air stream operatively associated with a blower.
A heating and ventilating unit of this type is known from the German Offenlegungsschrift (Laid-Open Specification) 22 08 377, in which a parallelepipedonal heat exchanger rests edgewise against a vertical wall of a fresh air duct in its cold position and may be pivoted about a lower transverse axis into its hot position completely spanning the fresh air duct.
The known heating and ventilating unit has various disadvantages. One disadvantage is that even when the heat exchanger is in the cold position, the fresh air flowing past it is heated in an undesirable manner. A further disadvantage is that a complicated deflection of the fresh air stream is necessary in order to achieve a favorable vertical flow through the heat exchanger.
Further disadvantages arise from the arrangement of the heat exchanger which is accessible only with difficulty and the blower disposed in the passenger compartment, as a result of which it is difficult to replace a defective heat exchanger on the one hand and a disturbing awareness of blower noises in the passenger compartment is to be expected on the other hand.